From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2199DCD342C for ; Wed, 6 May 2026 06:52:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ym3AiKeeVXG7wOa+iSCtIJhd+vnl3Yz5DjQm6LWMcgs=; b=BGzczaEFvEQF9IDU0hvOc/ApKL nzZ0Su8SDBmkhEdk9WDroHF9a3KkbqVytdBL+OQsilkH9uVjFZXawvhE9EBgIfkK7Zi/tJXMe0zp+ WEO9cQDfeBMQtE5b4WRLrWiwr97dnGofcwoRwVLebVAIHHCRfA/CIWsOpKv0ztL6C0UQGO3xOydfk C3JqDK2YekKYwMGY1sHbFZnJ7f9Fp8Z3FWECBt3Ra1Sa9zae5B21Z64Z7Qn8y2EZxSRaXOVmN4/m/ I3DOBMFkGbYqJ3kCod18NLcG5rpKXYdQDirILSiUIU4Qr3Hqof5fu4NLUJddc3yZ73LNCz/onDVWe ledmpVVg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wKW78-00000000wEe-2fBp; Wed, 06 May 2026 06:52:10 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wKW75-00000000wDb-3lS2 for linux-arm-kernel@lists.infradead.org; Wed, 06 May 2026 06:52:09 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1DF7F1691; Tue, 5 May 2026 23:52:01 -0700 (PDT) Received: from localhost (e132581.arm.com [10.1.196.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 269D63F763; Tue, 5 May 2026 23:52:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1778050326; bh=t37kJxEI2QhUVtL3vUNRO6SryV040GC23jsisBVSrHA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cTr+/A+/v3f0Dm2CgBeW5FYRqZPOLhQn/9ZZ/Yx46VdNsnzP9uOOhz8+EkOtAUP8T 8TQZNsoCCNy+RiSFn0/TlSRbA9vm6H15y2uzaR+CbaOaaNzPjWseOh3xCzQhZ0LoPQ RjG4h5HEFz5kBRLbEHVgcXIa7nVdSzTS0HRgqDpc= Date: Wed, 6 May 2026 07:52:04 +0100 From: Leo Yan To: James Clark Cc: Suzuki K Poulose , Mike Leach , Alexander Shishkin , Mathieu Poirier , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] coresight: ete: Always save state on power down Message-ID: <20260506065204.GB3778514@e132581.arm.com> References: <20260505-james-cs-ete-pm_save_enable-v3-1-485d21dd79b8@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260505-james-cs-ete-pm_save_enable-v3-1-485d21dd79b8@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260505_235207_996669_CF2DB07C X-CRM114-Status: GOOD ( 14.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, May 05, 2026 at 05:51:25PM +0100, James Clark wrote: > System register ETMs and ETE are unlikely to be preserved on CPU power > down. The ETE DT binding also never documented > "arm,coresight-loses-context-with-cpu" so nobody would have legitimately > been able to use that binding to fix it and ACPI has no such binding at > all. > > Fix it by hard coding the setting for sysreg ETMs (ETE is always sysreg) > or ACPI boots. Use a local variable when setting up save_state so that > it's immune to concurrent probing when devices have different > configurations which is an issue with modifying the global. > > This fixes the following error when using Coresight with ACPI on the FVP > which supports CPU PM: > > coresight ete0: External agent took claim tag > WARNING: drivers/hwtracing/coresight/coresight-core.c:248 at coresight_disclaim_device_unlocked+0xe0/0xe8, CPU#0: perf/117 > > Fixes: 35e1c9163e02 ("coresight: ete: Add support for ETE tracing") > Signed-off-by: James Clark Reviewed-by: Leo Yan